Is there a list of all nodes in blender?
Yes there is. However the list is much too long for an answer here. I have included a list of all the node types. There are many more nodes under each type classification. Click on the type you want to learn about. Or click the title for the section to view the index on the wiki.
Compositor Node Types:


Inputs
Outputs
Color
Vector
Filters
Converters
Mattes
Distortion
Groups


Material Node Types:


Input
Output
Color
Vector
Convertors
Groups
Dynamic
(PyNodes)


As for getting used to working with them, explore and experiment! You will stumble across all sorts of goodies. You can also try an online shading tutorial. Once you get better with nodes, I would suggest you try reaching a specific result, i.e. a Wood material, a Galvanized Steel material, etc.